Live Chat System for Website

I need a live chat software similar to a service called Olark which we currently use for my [login to view URL] need to be able to have multiple live chat representatives talking at the same time to different customers, and the service needs to be able to divide the customers between the multiple live chat agents and to assign customers to new live chat agents when they are disconnected. We would also like to be able to have the chat software linked to Google Talk so a representative can chat to customers using a smartphone. The live chat must match Olark in appearance, which you can see for yourself in action at Olark.com. It must also allow us to send an automatic message to our customers after a set amount. For example after 30 seconds of viewing the website the live chat will pop up with a message, "is there anything I can help you with?" That's all thanks.